Certain drugs (referred to herein as Active Pharmaceutical Ingredients or “API”) such as, for example, the opioid oxycodone, are administered to patients to reduce pain. Successful pain management in many of these patients requires maintenance of certain blood levels of the opioid throughout the day. One way of obtaining acceptable blood levels, used commonly in the pharmaceutical industry, is providing a dose which contains far more drug than is necessary to obtain the desired blood level. Blood levels shortly after the tablet is ingested reach a maximum or Cmax in a relatively short time, often within hours of ingestion (Tmax) and thereafter, as the body uses, processes and excretes drug from the blood system, the blood level drops. If the Cmax attained is sufficiently high, and the body's clearance of the drug is sufficiently slow, the blood levels may not fall to subtherapeutic levels for 4-12 hours or even longer. However, with drugs like oxycodone and indeed for many other drugs, this is an impractical and inefficient dosing system. In addition, there is a risk to the patient in that such high initial API levels can cause significant side effects.
Another method of administering drugs involves the use of an extended release mechanism. An extended release can be achieved in many different ways and there are many different release profiles that can be attained. For exemplification only, a granulate material can be produced with a material that when exposed to the digestive tract, swells with available fluids and either slowly erodes or slows the wetting and diffusion of API drug materials contained within the granulate, thus providing a much lower Cmax and often a much longer Tmax. Ideally, a zero order release is obtained whereby a constant release rate and a constant blood level is attained throughout an extended period of time often six hours or more, more preferably twelve hours or more, and most preferably over about 24 hours. Not only could this strategy reduce the number of doses that need to be taken in a day, it also may prevent one from being exposed to the side effects which can come from unnecessarily high initial blood levels.
Those who seek to abuse these types of products to “get high” can be frustrated by such extended and indeed other controlled release strategies. These strategies actively prevent one from obtaining high blood levels of the drug which can cause the euphoria or other physiologic effects which they are actually seeking, but which normal patients would consider an undesirable or even dangerous side effect. Such prescription drug abusers have learned to circumvent controlled release mechanisms by various administrative abuse means including simply chewing extended release tablets or crushing them using a mortar and a pestle for injection or the like. This can cause the rupture or otherwise compromise the API particle and/or controlled release coating, exposing more of the API to digestion and absorption more quickly, allowing the abuser to achieve much higher blood levels.
Such abuse can have rather far ranging consequences. First, it facilitates drug abuse by individuals which can lead to significant health consequences and even death for the abuser. The consequences of such abuse reach far beyond the abuser and his or her immediate family. Indeed, they can be societal as well. Useful drugs necessary for cancer patients, patients with post-operative or pre-operative pain, chronic pains from arthritis or back injuries need to have available products to allow them to cope. However, the potential for abuse is a constant concern to regulators and law enforcement as these often prescription drugs may be more freely obtainable than truly illegal illicit substances. There are also the societal problems relating to drug use, which includes the cost of their health care, the cost of their rehabilitation, the increase in crime which may come from supporting their drug habit and the like.
Ways of making a dosage form more crush resistant/abuse resistant include those disclosed in U.S. Patent App. Pub. No. 2006/0104909 and 2006/0193914. Coating pharmaceuticals or particles with various materials, which may include a fat/wax, to achieve other objectives, such as taste-masking, extended release, easier swallowing, etc. are also known. See, for example, U.S. Pat. Nos. 5,178,878; 5,607,697; 6,024,981; 6,280,770; 6,368,625; 6,692,771; 6,740,341; 2003/0180362; 2005/0163839; and 2007/0003617. See also U.S. Pat. No. 6,740,341, which discloses, inter alia, granulates coated with a dual layer coating one of which can include ethyl cellulose and HPMC.
Another way to circumvent controlled release coatings is to attempt to dissolve the dosage form in a solvent such as water or ethanol. The latter can be particularly dangerous as many prescription drugs should not be taken with alcohol. Depending upon the coating material used, the ethanol or water may act as a solvent, dissolving or eroding the coating and circumventing the intended controlled release. The resulting material can then be administered generally, orally, or in a syringe by a drug abuser.
There are several techniques which have been developed to deter this type of solvent abuse. One abuse deterrent system for oral opioid compounds is described in U.S. Published Application No. 2006/0177380. This disclosure describes a composition containing a gel forming polymer forming an obstacle to syringe uptake, and nasal/mucosal irritant that causes discomfort when excessive amounts of the active compound are inhaled. Such abuse-deterring systems often are designed for the nasal or parenteral abuse routes. See also U.S. Patent Application Publication Nos. 2006/0193914, 2006/0188447, 2006/0193782, 2006/0204573, 2002/0110595, WO 2006/079550, WO 2007/087452A2, U.S. Pat. Nos. 6,607,751 and 7,090,867. Uses of fax/waxes more generally are also described in US 2004/0116352. U.S. Pat. No. 5,500,227 discloses, the use of, inter alia, waxes and fatty alcohols in a coating to provide sustained release.